What is the nature of practical reason? This is a question that has occupied the minds of Islamic and Western philosophers, and each has answered it based on their own philosophical system. Among the Islamic sages is Qutb al-Din al-Razi, and among the Western philosophers is Baruch Spinoza, who have come forward to answer it. In Qutb al-Din al-Razi's view, reason is a commonality of the two powers of knowledge and action; because the work of theoretical reason is in some way affected by reality and has a passive identity, and the work of practical reason is in some way affected by reality and has an active identity. However, from Spinoza's point of view, the will to know is a confirmation, and confirmation is also a state of complete conception. Therefore, the will is a state of complete conception, and since complete conception is the same as reason. Therefore, the will is the same as reason; accordingly, reason in his thinking is only theoretical reason that only knows and confirms and denies, and he does not accept practical reason in the sense that previous philosophers used to say.